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Santorum: 'Pennsylvania, you know me'

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Story highlights

Despite losses and falling behind in delegate race, Santorum will fight on

Santorum predicts victory in home state of Pennsylvania on April 24

Conservative states in May look friendlier to Santorum

Santorum draws parallels to Ronald Reagan's failed 1976 campaign

Despite disappointing finishes in all three of Tuesday's Republican primaries, Rick Santorum indicated no sign of letting up in his quest to win the Republican presidential nomination.

"The clock starts tonight," Santorum said to supporters in Pennsylvania. "Half the delegates in this process have been selected, and who's ready to charge out of the locker room in Pennsylvania for a strong second half?"

Speaking on familiar turf, the former two-term senator from the Keystone State urged supporters to dismiss attacks from his opponents ahead of Pennsylvania's primary later in April.

"You know me. You know how hard I work," Santorum said. "They'll say all the things, that I'm someone who doesn't stand up for what I believe in. You know me."

In recent days, Santorum has predicted he will win his home state's contest, which has 72 delegates at stake. He also expects to push on through May, a month that holds contests in states that are more conservative.

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Santorum looking forward to May

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But exit poll data from Tuesday's primaries reveal Santorum could be losing his grip on that key constituency. In Wisconsin, Romney picked up more support from conservatives, evangelicals and tea party supporters than Santorum did.

The former senator fought aggressively for conservative votes in Wisconsin, crisscrossing the state over nine days, making as many as six stops a day.

He held rallies at a number of bowling alleys, even swapped his cowboy boots for bowling shoes to bowl with friends, family and locals. During his first game in Sheboygan on March 24 he bowled three strikes in a row -- a turkey. Pretty good for a guy who used to bowl as a kid but said he hadn't in a number of years.

Later that night, he scored again when he won Louisiana's Republican primary, which was his 11th primary or caucus win. He celebrated that victory in Green Bay, Wisconsin, enjoying local beer and playing shuffleboard at Titletown Brewing Co.

But Romney's campaign and those backing him laid down a barrage of negative advertising and robocalls that took a toll on Santorum's small-budget campaign. It wasn't until the day before the primary that his team released a campaign ad in Wisconsin suggesting Romney's policies are similar to the Democratic incumbent Obama.

Romney swooped into the state and picked up significant endorsements that helped secure his win.

In an interview on Monday on CNN's "Piers Morgan Tonight," Santorum acknowledged that "April would be a very tough month for us," but he intends to compete through May and onto the convention.

"May is rich with delegates and are strong states for us -- states like Texas and Arkansas and Kentucky and Indiana, West Virginia, North Carolina. Those are the states that we know we can get this back, right back to where it is right now, which is a lot closer than what Mitt Romney and the pundits are spinning," he said.

In Santorum's primary night speech in Mars, Pennsylvania, just miles from Butler, where he was raised, he took swipes at his GOP opponent but did not repeat the line from a speech in Franksville on March 25, in which he said the front-runner was the "worst Republican in the country to put up against Barack Obama" in the general election.

As he continued to try to tie Romney to Obama, Santorum again compared his campaign to President Ronald Reagan's failed 1976 presidential run.

"[Reagan] was able to stand tall and in May win the state of Texas, which we have every intention of doing," Santorum said and the crowd chanted "Go, Rick, Go!"

"He took that race the entire way to the convention and he fell short, and in the fall Republicans fell short because we nominated another moderate who couldn't galvanize our party and bring those votes to our side to get the kind of change we needed in America."

If Santorum is on a similar trajectory to the White House as Reagan, then he may very well be running again in four years.